Load cell weigh module hat limits horizontal floating movement of the top plate

ABSTRACT

A weigh module ( 1 ) includes a load cell ( 2 ), a base plate ( 3 ), a top plate ( 6 ), a force-transmitting member ( 8 ) serving to transmit the weighing force from the top plate ( 6 ) to the load cell ( 2 ), and movement-restricting means ( 9, 10 ) which serve to limit the horizontal floating movement of the top plate ( 6 ) relative to the base plate ( 3 ) within a confined range of free play and to transmit lateral force components directly from the top plate ( 6 ) to the base plate ( 3 ). One part of the movement-restricting means ( 9, 10 ) has the form of a channel whose top edges ( 11 ) are rigidly connected to the top plate ( 6 ) and whose flat bottom extends parallel to the base plate ( 3 ) at a clear distance from the latter. The other part of the movement-restricting means ( 9, 10 ) is a bolt whose shaft ( 15 ) is anchored in the base plate ( 3 ) and passes with all-around clearance through a passage ( 14 ) in the channel bottom ( 13 ), and whose head ( 16 ) is larger than the passage ( 14 ) and arranged above the channel bottom ( 13 ) with a vertical clearance gap from the latter.

BACKGROUND OF THE INVENTION

The invention concerns a weigh module for installation in a weighingscale of the kind where a weighing load carrier such as for example aplatform, a tank, a hopper, or a belt conveyor is supported by aplurality of weigh modules, wherein each weigh module contains a loadcell and the weight of a load on the weighing load carrier is determinedby summation of the individual load cell signals.

A conventional weigh module includes a base part that can be bolted to afoundation or support structure, a top part that can be bolted to theweighing load carrier, a load cell that is fastened to the base part,and a force-transmitting member which is arranged between the top partand the load cell and serves to introduce the weighing force from thetop part into the load cell. The function of the weigh module is toensure that only the substantially vertical weight force that is to bemeasured is received by the load cell, while laterally directed forcesand/or relative displacements between the top part and the base partwhich could harm the load cell or compromise the weight measurement areprevented from reaching the load cell.

In an installation of this kind, lateral forces or relativedisplacements between the top parts and the bases of the weigh modulescan arise for example as a result of different thermal expansions of theweighing load carrier and the foundation or support structure,deformation of the weighing load carrier caused by the weighing load,seismic shifts, wind forces, braking and acceleration of vehicles on avehicle scale, and other forces originating from inside or outside theweighing scale.

To protect the load cell from having to absorb lateral forces and/ordisplacements, the force-transmitting member may be configured, forexample, as a so-called rocker pin, a construction element generallyknown to those of ordinary skill in the relevant art. Arranged invertical orientation between the top part and a load-introduction areaor -element of the load cell, a rocker pin transmits a force along itslongitudinal axis while essentially yielding to transverse forces anddisplacements of the top part, resisting such forces and displacementsonly through its inherent but very limited capability to maintain and/orrestore its vertical orientation. Besides rocker pins, the state of theart also includes force-transmitting members in which a self-rightingresilience is achieved in different ways, for example by insertingelastomeric pads in the contact zones where the upper and lower end ofthe force-transmitting member meet, respectively, the top part of theweigh module and the force-introduction zone of the load cell.

To absorb transverse forces and displacements that exceed the limitedposition-restoring ability of the force-transmitting member, weighmodules normally include means to restrict or constrain the freedom oflateral movement of the top part in relation to the base part. Amovement-restricting means is generally of the nature of a solidboundary which confines movement of the top part relative to the basepart in any horizontal direction to a limited zone of free play and isstrong enough to withstand horizontal forces within given designspecifications.

The restricting means may further be designed with the capability tostop vertical upward movement of the top part and thus to prevent theweighing load carrier (which is fastened to the top part) from beinglifted off the base, for example by wind forces. Finally, therestricting means may include a stop to prevent an excessive downwarddrop of the weighing load carrier in case of a mechanical collapse ofthe load cell.

In addition to the restricting means in the form of movement-stoppingboundaries, a weigh module may also include constraints, for example inthe form of horizontal checkrods linking the top part to the bottom partand thereby inhibiting any linear movement of the top part relative tothe base part in the direction of the checkrod.

However, in an arrangement of weigh modules that are thus constrained inone or two horizontal directions, care must be taken to avoidover-constraints. For example, a platform scale with four weigh modulescould have three weigh modules with one checkrod each and a fourth weighmodule without checkrod, arranged in such a way that no two of thecheckrods are collinear with each other.

The actual arrangement and configuration of the aforementioned genericelements in a weigh module depends to a large extent on the type of loadcell, the primary distinction being between so-called canister loadcells and cantilever beam load cells. A canister load cell generally hasthe shape of an upright cylinder whose bottom is fastened to the baseplate of the weigh module. The weighing force is directed substantiallyalong the axis of the cylinder and is applied to a so-called load buttonat the center of the top surface of the upright cylinder.

A variant of the canister load cell, the so-called rocker pin load celllikewise has the form of an upright cylinder. However, both the top andbottom are spherically shaped rocker surfaces. Installed in a weighmodule, this load cell is arranged like a rocker pin between the toppart and the base part of the weigh module. In other words, the rockerpin load cell combines the functions of load cell and force-transmittingmember in one integral unit.

In contrast to the canister load cell or the rocker pin load cell, acantilever beam load cell is basically configured as a horizontal beamwhich, when installed in a weigh module, is at one end solidly connectedto the base of the weigh module while the opposite, free end of thecantilever beam receives the weighing load from the top part of theweigh module by way of a force-transmitting member.

The following examples of the state of the art illustrate specificembodiments of the foregoing generic concepts of weigh modules.

A weigh module according to U.S. Pat. No. 6,331,682 has a base part anda top part in the form of flat plates with mounting holes for theirattachment to a foundation or support structure and to a weighing loadcarrier such as a tank or a platform. The load cell in this weigh moduleis configured as a canister load cell, and the force-transmitting memberis configured as a rocker pin. Movement-restricting means are providedin the form of four lower block-shaped posts rising up from the baseplate on opposite sides of the load cell and two upper block-shapedposts descending downward from the top plate into interstices betweenthe lower block-shaped posts, leaving lateral play between the upper andlower block-shaped posts. Horizontally oriented restraining pins areheld with a tight fit in seating holes in the lower block-shaped postsand pass with all-around free play through clearance holes in the upperblock-shaped posts. Movement of the top plate relative to the base plateis thus restricted: a.) in a horizontal x-direction by the horizontalplay between pins and clearance holes; b.) in a horizontal y-directionby the lateral play between the upper and lower block-shaped posts; andc.) in a vertical z-direction (upward and downward) by the vertical playbetween pins and clearance holes. With more than one movement-stoppingcontact area in each direction, this weigh module has a designredundancy that does not appear to be justifiable. When the weigh moduleis pushed laterally in any given direction, the respective stop contactscannot be expected to engage simultaneously, and their redundancy willtherefore not increase the capability of the weigh module to withstandlateral forces. Also, visual inspection of all clearances appears to berather cumbersome, and the horizontal passage holes in the block-shapedposts may be prone to collect dirt and debris which could compromise theweighing accuracy. In addition, the fabrication and assembly of sixblock-shaped posts and two pins gives the impression of being relativelyexpensive to realize in practice.

A weigh module described in U.S. Pat. No. 3,997,014 has a base part inthe form of a flat plate and a top part in the form of an angle profilewith a horizontal and a vertical portion, with the vertical portionhaving mounting holes through which the top part can be bolted sidewaysto a vertical surface of the weighing load carrier. The load cell inthis weigh module is configured as a rocker pin load cell which performsthe combined functions of load sensor and force-transmitting member asdescribed hereinabove. Movement-restricting means are provided in theform of two vertical posts rising up from the base plate on oppositesides of the load cell and by clearance holes in the horizontal portionof the angular top part, wherein the upper extremities of the verticalposts reach into the clearance holes with lateral play, thus performingthe lateral movement-restricting function. Like the preceding example,this weigh module again has redundant movement-stopping elements whosecontributions in absorbing horizontal forces may not necessarily beadditive. Besides, free-standing cylindrical posts do not appear to bethe most efficient design for the absorption of transverse forces.

A weigh module according to DE 199 18 408 A1 has a base part and a toppart in the form of flat plates, with a rocker pin load celltransmitting and simultaneously measuring the weighing force between thetop plate and the base plate. Also mentioned in this reference is thepossibility of using elastomeric bearings rather than spherical rockersurfaces for the introduction of the weighing force and its equal andopposite reaction force into the load cell. A first movement-restrictingpart is provided in the form of a massive cylindrical bumper post risingup from the base plate and carrying at the top a rectangular plate. Asecond movement-restricting part has the form of an angular profiledescending from the top plate. The corner ends of the rectangular platereach into cutouts of the angular profile, wherein the clearancesbetween the projections and the edges of the cutouts delimit the freemovement of the top part relative to the base part in an x-directiontowards (but not away from) the load cell and both ways in they-direction perpendicular to the x-direction. Full restriction ofhorizontal movement in all directions is achieved by orienting theindividual way modules of an installation appropriately, so that theirrespective movement-blocking capabilities complement each other. An areaof concern with this weigh module would be the cost and feasibility ofconnecting the massive post to the base plate, the rectangular plate tothe post, and the angular profile to the top plate either by welding orby means of screw bolts.

An example of a weigh module with a lateral constraint in the form ofone horizontal checkrod is illustrated in FIG. 2 of DE 101 38 435 A1. Bylinking the top part to the bottom part, the checkrod inhibits linearmovement of the top part relative to the base part in the direction ofthe checkrod. Horizontal movements transverse to the direction of thecheckrod are limited within a range of free play between a first and asecond part of a movement-restricting means. As mentioned above, byarranging three such weigh modules with their checkrods oriented alongnon-collinear axes, it is possible to build a weighing scale withoutloose play between the weighing load carrier and the supporting basewhile at the same time avoiding over-constraints that would introducelateral forces into the load cells. In a scale with more than threeweigh modules, one would simply omit the checkrod from the fourth andany further weigh modules used in the installation. This weigh module,too, suffers from the drawback of being complicated and expensive torealize in practice. A welded table-like structure which forms a firstmovement-restricting part rises from the base plate to within a narrowdistance of the top plate, while separate holder brackets for thebearings of the checkrod are also welded to the base plate and the topplate, respectively.

OBJECT OF THE INVENTION

In view of the shortcomings of the prior art, particularly thecomplexity and expense involved in manufacturing weigh modules accordingto the proposed concepts, it is therefore the object of the presentinvention to create a load cell weigh module that offers superiorstructural strength in withstanding lateral as well as vertical forces,allows improved visual inspection of all clearances, and reduces thepotential for accumulation of dirt and debris that could compromiseweighing accuracy, while being at the same time simple andcost-effective to manufacture as well as easy to transport, to installand to maintain.

The invention is particularly directed—but not limited—to a weigh modulethat accommodates a cantilever beam load cell, and further to a weighmodule that can be equipped with a checkrod.

SUMMARY OF THE INVENTION

A weigh module according to the present invention includes:

-   -   a load cell,    -   a substantially flat base plate on which the load cell is        mounted and which serves to connect the weigh module to a        foundation or understructure,    -   a substantially flat top plate which serves to connect the weigh        module to a weighing load carrier such as for example a weighing        platform or a weighing tank,    -   a force-transmitting member arranged between the top plate and        the load cell and serving to transmit a downward-directed and        substantially vertical weighing force from the top plate to the        load cell, and    -   movement-restricting means which serve to limit horizontal        relative movement between the top plate and the base plate        within a confined range of free play and to transmit lateral        force components directly from the top plate to the base plate,        thereby preventing any lateral forces acting on the top plate        from reaching the load cell.

In the weigh module according to the invention, the movement-restrictingmeans include an upper movement-restricting part rigidly connected tothe top plate and a lower movement-restricting part rigidly connected tothe base plate. In particular, the upper movement-restricting part hasthe form of a channel with side walls whose top edges are attached tothe top plate, and with a flat channel bottom extending parallel to thebase plate at a clear distance from the latter. The lowermovement-restricting part is formed by an upright bolt, whose shaftpasses with all-around clearance through a passage in the channel bottomand is anchored in the base plate. The bolt has a head that is largerthan the passage and, in the installed position of the bolt, is locatedat a clear distance above the channel bottom. Thus, relative movementbetween the top plate and the base plate is restricted in any lateraldirection, as the bolt shaft is stopped by the boundary of the passagein the channel bottom. Lift-off of the top plate, for example due towind forces, is restricted as the border area of the channel bottomopening is stopped by the bolt head, while downward collapse of theweigh module, for example due to mechanical failure of the load cell, isprevented as the base plate stops the downward movement of the channelbottom.

In a preferred embodiment of the weigh module according to theinvention, the upper movement-restricting part is made of plate materialand receives its profile shape by bending the channel sides up from thechannel bottom.

Preferably, the top edges of the channel sides are connected to the topplate by welding.

The preferred profile shape for the channel of the uppermovement-restricting part is a symmetrical trapezoid with a greaterwidth between the top edges than across the flat channel bottom. Inparticular the trapezoidal shape provides more structural strengthagainst lateral forces directed perpendicular to the bending foldsbetween the channel bottom and channel sides.

The structural strength against lateral forces directed perpendicular tothe bending folds between the channel bottom and channel sides isfurther enhanced in an embodiment where stiffening profiles areimpressed in the channel sides.

The bolt which forms the lower movement-restricting part can run througha tubular bushing with a bushing collar, wherein the bushing has asmaller diameter and the bushing collar has a larger diameter than thepassage in the trapezoidal channel, so that there is an all-aroundlateral clearance gap between the bushing and the rim of the passage andan upward vertical clearance gap between the bushing collar and thechannel bottom. The tubular bushing with the bushing collar thus servesto precisely define the range of vertical movement of the uppermovement-restricting part relative to the lower movement-restrictingpart, and it also serves as a spacer block against which the bolt can betightened.

The force-transmitting member is preferably a rocker pin which isarranged in a substantially vertical position between the top plate andthe load cell. The upper end of the rocker pin is in compressive,force-transmitting contact with a load-bearing element of the top plateand the lower end of the rocker pin is in compressive,force-transmitting contact with a load-receiving element of the loadcell.

The load cell in preferred embodiments of the weigh module according tothe invention can be a cantilever load cell with a mounting portionrigidly attached to the base plate, with a cantilever arm extending in asubstantially horizontal direction from the mounting portion, and with aload-receiving portion arranged at the free end of the cantilever arm.

Furthermore, in preferred embodiments of the weigh module according tothe invention with a cantilever load cell, the cantilever arm reacheswith all-around clearance into the space that is enclosed between thetop plate, the channel sides and the channel bottom.

A further preferred embodiment of the weigh module according to theinvention includes a constraint in the form of a horizontal checkrod,wherein one end of the checkrod is pivotally connected to a first swivelbearing incorporated in one of the channel sides and the other end ofthe checkrod is pivotally connected to a second swivel bearingincorporated in a post that is mounted on the base plate.

In contrast to restricting means which allow relative movement betweenthe top plate and the base plate within defined narrow limits, acheckrod absolutely inhibits movement in the direction of its ownlongitudinal axis. In other words, a checkrod removes one degree offreedom from the mobility of the top plate relative to the base plate.

A weigh module according to the invention may further include animmobilizer device which, for transport and installation of the weighmodule, is interposed between the upper movement-restricting part andthe base plate and secures the position of the uppermovement-restricting part relative to the base plate. In the operatingstate of the weigh module, the immobilizer device is taken out.Equipping the weigh module with an immobilizer device has proven to beadvantageous in that it allows the weigh module to be installed withouta load cell while maintaining proper relative positioning between thetop plate and the base plate. Thus the weigh module can be installed atone time and the load cell at a later time. It also allows the weighmodule to be used as an inactive stand when the load cell is removed forservicing or replacement.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is hereinafter described through preferred embodiments asillustrated in the accompanying drawings, wherein:

FIG. 1 shows a weigh module according to the invention with a cantileverbeam load cell seen (1A) in transverse cross-section and (1B) in alongitudinal section;

FIG. 2 shows a perspective view of an embodiment of the uppermovement-restricting part with press-formed stiffener profiles;

FIG. 3 shows a weigh module according to the invention equipped with acheckrod seen in transverse cross-section (3A) and in a side elevationdrawing (3B);

FIG. 4 shows a weigh module according to the invention in aconfiguration that is adapted to a canister type load cell; and

FIG. 5 shows a weigh module according to the invention with animmobilizer device in a side elevation drawing (5A), and the base platewith the immobilizer device in a perspective view (5B).

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A and 1B show sectional views of a weigh module 1 with acantilever load cell 2. FIG. 1A represents a cross-section in a planeA-A as indicated in FIG. 1B, i.e. transverse to the beam direction ofthe cantilever load cell 2. FIG. 1B represents a longitudinal section ina plane B-B as indicated in FIG. 1A, i.e. a vertical plane bisecting thecantilever load cell 2 in the lengthwise direction. The weigh module 1has a base plate 3 with mounting holes 4 allowing the base plate to bebolted to a foundation or support structure (not shown in the drawing).The cantilever load cell 2, outlined here in the shape of a rectangularslab which is typical of so-called shear beam load cells, is rigidlymounted on the base plate 3, vertically elevated from the latter by aspacer block 5. The weigh module 1 further has a top plate 6 withmounting holes 7 that allow the top plate 6 to be bolted to a weighingload carrier such as a weighing platform or a weighing tank (not shownin the drawing). A force-transmitting member 8, shown here in the formof a rocker pin, is arranged between the top plate 6 and the load cell 2to transmit a substantially vertical, downward-directed weighing forcefrom the top plate 7 to the load cell 2. The function of the rocker pin8 is to provide a so-called “floating” support of the top plate 7 on theload cell 2, wherein no horizontal force-components are transmitted tothe load cell. Movement of the top plate 7 relative to the base plate 3is restricted by movement-restricting means 9, 10 constituted by anupper movement-restricting part 9 connected to the top plate 7 and alower movement-restricting part 10 connected to the base plate 3. In theview of FIG. 1A, the upper movement-restricting part 9 presents theprofile of a trapezoidal channel which is wider between the top edges 11of the channel sides 12 than across the channel bottom 13. Thechannel-shaped upper movement-restricting part 9 is typically formed ofplate material and is attached to the top plate 7 by weld seams alongthe top edges 11. The channel bottom 13, which contains a round passage14, extends parallel to the base plate 3 at a clear distance from thelatter. The lower movement-restricting part 10 has the form of a bolt15, 16 with a bolt shaft 15 which is anchored in the base plate 3 andpasses through the passage 14 with an all-around circular clearance gapbetween the bolt shaft 15 and the rim of the passage 14. The bolt head16, which is larger in diameter than the passage 14, is located at aclear distance above the channel bottom 13. The aforementioned circularclearance gap and the clear distances in the upward and downwarddirection, typically of the order of a few millimeters, limit the rangeof the horizontal floating movement of the top plate 7 and also restrictvertical upward and downward movement to prevent lift-off as well as acatastrophic drop of a load carrier supported by three or more weighmodules 1.

In combination with a cantilever load cell 2, the inventive concept ofthe upper movement-restricting part 9 as a channel has a particularadvantage that it leads to a very compact design of the weighing module1, with the cantilever arm of the load cell reaching into the spacedelimited by the channel profile. Furthermore, the position of the bolt15, 16 near the front end of the weigh module 1 (see FIG. 1B) providesideal visibility to inspect the required all-around clearance betweenthe bolt 15, 16 and the passage 14 and to detect possible accumulationsof dirt and debris which could compromise the functioning of theweighing apparatus in which the weigh module is installed.

FIG. 2 shows a perspective view of a channel-shaped uppermovement-restricting part 109 in which the channel sides 112 includepress-formed stiffening profiles 120. This increases the strength of theupper movement-restricting part 109 to withstand lateral forcesparticularly in the direction transverse to the channel. The holes 121in the channel sides 112 serve to hold swivel bearings for checkrods,which will be explained in FIG. 3. The function of the rectangularcutout 141 in the channel bottom 113, which is also present as cutout441 in the channel bottom 413 of FIG. 5A, will be explained in thecontext of FIG. 5.

FIG. 3A shows a sectional view and FIG. 3b shows a side view of a weighmodule 201 analogous to FIGS. 1A, and 1B, wherein the load cell has beenomitted for better clarity. The weigh module 201 is equipped with acheckrod 230 which is connected through swivel bearings 231, 232,respectively, to the upper movement-restricting part 209 and to a post233 that is solidly connected to the base plate 203. The checkrod 230constrains the top plate 206, and thus a load carrier connected to thelatter, from moving in the longitudinal direction of the checkrod 230.Of course, there could also be checkrods 230 arranged in parallel onboth sides of the upper movement-restricting part 209. Although anarrangement with three checkrod-equipped weigh modules 201 willpositively constrain any horizontal floating movement of a load carrier,the lower movement-restricting part 210 is still required to prevent thetop plate 206 from lifting off, for example in case of an earthquake orstrong wind forces.

As the weigh module 301 in FIG. 4 illustrates, the invention is notlimited to weigh modules with a cantilever load cell. To accommodate acanister load cell 302, the channel profile of the uppermovement-restricting part 309 is cut off at an appropriate angle at theedge 335 that faces towards the load cell 302, while all other parts canremain identical. As a further alternative, the arrangement of acanister load cell 302 with a rocker pin 308 shown in FIG. 4 could alsobe replaced by a so-called rocker pin load cell (not shown in thedrawings).

FIG. 5A shows an example of an immobilizer device in the form of a shimplate 440 which is inserted between the base plate 403 and the channelbottom 413 of a weigh module of the same embodiment as in FIG. 3. As isevident from the slightly inclined position of the checkrod 430, theshim plate 440 is thicker than the height of the air gap which existsbetween the channel bottom 413 and the base plate 403 when the weighmodule 401 is in its operating state. Thus the channel bottom 413 ispushed up against the collar 437 of the bushing 436.

For better clarity, FIG. 5B gives an open view of the shim plate 440 inits normal position on the base plate 403. At the front end (relative tothe view of FIG. 5B) the shim plate 440 has a cutout that embraces thebushing 436. The end of an arm of the shim plate 440 extending to therear has another cutout which serves to secure the shim plate 440 on thebase plate 403 by installing a bolt 444 (FIG. 5A) in a threaded hole 443of the base plate 403. An upward-bent tongue 442 of the shim plate 440fits precisely into a conforming cutout 441 of the channel bottom 413(shown more clearly as cutout 141 in the channel bottom 113 of FIG. 2),whereby the upper movement-restricting part 409 with the top plate 406is secured against movement in the direction transverse to the channel,while movement in the lengthwise direction of the channel is alreadyconstrained by the checkrod 430.

As mentioned previously, an immobilizer device (for which the shim plate440 of FIG. 5 represents a possible example) is advantageous for keepingthe parts of the weigh module firmly positioned relative to each otherwhen the weigh module is not in its operating state in a weighingapparatus, i.e. for example during transport and installation of theweigh module. With the immobilizer device in position, it is possible toinstall the weigh module without a load cell while maintaining properrelative positioning between the top plate 406 and the base plate 403.Thus the weigh module 401 can be installed at one time and the load cellat a later time. It can also be advantageous to re-insert theimmobilizer device 440 in the weigh module 401 when the load cell isremoved for servicing or replacement, so that the weigh module 401functions as a secure stand during the inactive period of the weighingscale.

While the inventive weigh module has been described and illustratedthrough certain preferred embodiments, it should be evident thatnumerous variations could be created based on the teachings of thepresent invention, for example by an upside-down arrangement of theentire weigh module of FIG. 1, 3, 4 or 5 or at least parts of it, forexample so that the channel is fastened to the base plate and forms thelower movement-restricting part, while the bolt is fastened to the topplate and forms the upper movement-restricting part. Accordingly, suchvariations are considered to be included in the invention.

LIST OF REFERENCE SYMBOLS

-   -   1, 201, 301, 401 weigh module    -   2, 302 load cell    -   3, 203, 403 base plate    -   4 mounting holes    -   5 spacer block    -   6, 206, 306, 406 top plate    -   7 mounting holes    -   8, 308 force-transmitting member, rocker pin    -   9, 109, 209, 309, 409 upper movement-restricting part    -   10, 210, 410 lower movement-restricting part    -   11 top edges    -   12, 112, 212, 412 channel sides    -   13, 113, 312, 413 channel bottom    -   14, 114 passage in channel bottom    -   15 bolt shaft    -   16 bolt head    -   120 press-formed stiffening profiles    -   121 holes for checkrod bearings    -   141, 441 cutout, recess    -   230, 430 checkrod    -   231, 232 checkrod bearings    -   233 post    -   236, 436 bushing    -   237, 437 collar of bushing    -   335 edge of 309    -   440 immobilizer device    -   442 upward-bent tongue    -   443 tapped hole

The invention claimed is:
 1. A weigh module, comprising: a load cell; abase plate that is substantially flat, on which the load cell is mountedand which serves to connect the weigh module to a supporting base; a topplate that is substantially flat, which serves to connect the weighmodule to a weighing load carrier supporting a weighing load; aforce-transmitting member arranged between the top plate and the loadcell and serving to transmit a downward-directed and substantiallyvertical weighing force from the top plate to the load cell; and a meansfor restricting movement to limit horizontal relative movement betweenthe top plate and the base plate within a confined range of free playand to transmit lateral force components directly from the top plate tothe base plate, thereby preventing said lateral force components fromreaching the load cell, said movement-restricting means comprising: anupper movement-restricting part rigidly connected to the plate, theupper movement restricting part in the form of a trapezoidal channelwith channel sides having top edges attached to the top plate and with aflat channel bottom containing a passage and extending parallel to thebase plate at a clear distance therefrom, the trapezoidal channel havinga greater width between the top edges than across flat channel bottom;and a lower movement-restricting part rigidly connected to the baseplate, comprising a bolt with a shaft and a head, the bolt beinganchored in the base plate with the bolt shaft passing through saidpassage in the channel bottom, leaving an all-around lateral clearancegap between the bolt shaft and the passage and an upward verticalclearance gap between the bolt head and the channel bottom.
 2. The weighmodule of claim 1, wherein the upper movement-restricting part is madeof plate material and shaped into said channel form by bending thechannel sides up from the channel bottom.
 3. The weigh module of claim2, wherein the top edges of the channel sides are connected to the topplate by welding.
 4. The weigh module of claim 3, wherein the channelsides comprise press-formed stiffening profiles.
 5. The weigh module ofclaim 1, wherein the lower movement-restricting part further comprises abushing with a bushing collar surrounding the bolt shaft, leaving anall-around lateral clearance gap between the bushing and the passage andan upward vertical clearance gap between the bushing collar and thechannel bottom.
 6. The weigh module of claim 1, wherein theforce-transmitting member comprises a rocker pin having an upper end anda lower end, the rocker pin arranged in a substantially verticalposition between the top plate and the load cell such that the upper endof the rocker pin is in compressive force-transmitting contact with aload-bearing element of the top plate and the lower end of the rockerpin is in compressive force-transmitting contact with a load-receivingportion of the load cell.
 7. The weigh module of claim 1, wherein theload cell is a cantilever load cell with a mounting portion rigidlyattached to the base plate, with a cantilever arm extending in asubstantially horizontal direction from the mounting portion, and with aload-receiving portion arranged at a free end of the cantilever arm. 8.The weigh module of claim 7, wherein the cantilever arm reaches withall-around clearance into a space delimited by the top plate, thechannel sides and the channel bottom.
 9. The weigh module of claim 1,further comprising: a first swivel bearing incorporated in one of thechannel sides; a second swivel bearing connected to the base plate; anda checkrod, the ends of which are pivotally connected to the respectiveswivel bearings, serving to constrain one degree of freedom ofhorizontal movement of the top plate relative to the base plate.
 10. Theweigh module of claim 1, further comprising: an immobilizer device whichis interposed between the upper movement-restricting part and the baseplate and secures the position of the upper movement-restricting partrelative to the base plate during transport and installation of theweigh module, and which is subsequently removed to put the weigh moduleinto its operating state.
 11. The weigh module of claim 2, wherein thechannel sides comprise press-formed stiffening profiles.
 12. The weighmodule of claim 1, wherein the upper movement-restricting part is madeof plate material and shaped into said channel form by bending thechannel sides up from the channel bottom.
 13. A weigh module,comprising: a cantilever load cell, having a mounting portion from whicha cantilever arm extends in a substantially horizontal direction, with aload-receiving portion arranged at a free end of the cantilever arm; abase plate that is substantially flat, to which the mounting portion isrigidly attached and which serves to connect the weigh module to asupporting base; a top plate that is substantially flat, which serves toconnect the weigh module to a weighing load carrier supporting aweighing load; a force-transmitting member arranged between the topplate and the load cell and serving to transmit a downward-directed andsubstantially vertical weighing force from the top plate to the loadcell, the force-transmitting member comprising a rocker pin having anupper end and a lower end, the rocker pin arranged in a substantiallyvertical position between the top plate and the load cell, such that theupper end of the rocker pin is in compressive force-transmitting contactwith a load-bearing element of the top plate and the lower end of therocker pin is in compressive force-transmitting contact with aload-receiving portion of the load cell; and a means for restrictingmovement to limit horizontal relative movement between the top plate andthe base plate within a confined range of free play and to transmitlateral force components directly from the top plate to the base plate,thereby preventing said lateral force components from reaching the loadcell, said movement-restricting means comprising: an uppermovement-restricting part rigidly connected to the top plate and in theform of a channel with channel sides having top edges attached to thetop plate and with a flat channel bottom containing a passage andextending parallel to the base plate at a clear distance therefrom; anda lower movement-restricting part rigidly connected to the base plate,comprising a bolt with a shaft and a head, the bolt being anchored inthe base plate with the bolt shaft passing through said passage in thechannel bottom, leaving an all-around lateral clearance gap between thebolt shaft and the passage and an upward vertical clearance gap betweenthe bolt head and the channel bottom; wherein the cantilever arm reacheswith all-around clearance into a space delimited by the top plate, thechannel sides and the channel bottom.
 14. A weigh module, comprising: acantilever load cell, having a mounting portion with a cantilever armextending substantially horizontally therefrom and a load-receivingportion arranged at a free end of the cantilever arm; a base plate thatis substantially flat, to which the mounting portion of the cantileverload cell is rigidly attached and which serves to connect the weighmodule to a supporting base; a top plate that is substantially flat,which serves to connect the weigh module to a weighing load carriersupporting a weighing load; a force-transmitting member arranged betweenthe top plate and the load cell and serving to transmit adownward-directed and substantially vertical weighing force from the topplate to the load cell; and a means for restricting movement to limithorizontal relative movement between the top plate and the base platewithin a confined range of free play and to transmit lateral forcecomponents directly from the top plate to the base plate, therebypreventing said lateral force components from reaching the load cell,said movement-restricting means comprising: an uppermovement-restricting part rigidly connected to the plate, and in theform of a channel with channel sides having top edges attached to thetop plate and with a flat channel bottom containing a passage andextending parallel to the base plate at a clear distance therefrom; anda lower movement-restricting part rigidly connected to the base plate,comprising a bolt with a shaft and a head, the bolt being anchored inthe base plate with the bolt shaft passing through said passage in thechannel bottom, leaving an all-around lateral clearance gap between thebolt shaft and the passage and an upward vertical clearance gap betweenthe bolt head and the channel bottom; wherein the cantilever arm reacheswith all-around clearance into a space delimited by the top plate, thechannel sides and the channel bottom.